Short answer: 3D puff is satin stitched over a sheet of foam. Digitize only bold shapes as puff, using satin columns about 3–10 mm wide. Use very little underlay under the puff, sew the satin dense enough to perforate the foam along both edges, cap every open column end so the foam is cut there too, and put a machine stop before the puff so the operator can lay the foam down. Keep small text and thin lines flat.
Puff embroidery gives raised, sculpted letters. It's the signature look on structured caps. It only works when the file is built for it. A flat design sewn over foam looks lumpy, with foam poking out of every open end.
How puff works
- The machine sews the flat parts of the design.
- It stops. The operator lays a sheet of puff foam (commonly 2–3 mm thick, in a colour close to the thread) over the area.
- The machine sews the puff satins over the foam. The needle penetrations along each edge perforate the foam.
- The leftover foam is torn away. What's left is foam wrapped in thread.
Every decision in a puff file comes from that sequence: the stitches have to cover the foam, perforate it cleanly, and close it off at the ends.
What can be puff and what should stay flat
Puff needs bold, simple shapes:
- Good: block letters, thick outlines, bold numbers, simple icons.
- Stay flat: thin script, small text, fine lines, detailed artwork, large fills.
Many of the best cap designs combine both: a bold puff word or initials with smaller flat lettering or a flat outline.
Column width: 3 to 10 mm
- Narrower than about 3 mm: the column can't hold the foam up. It pokes through or flattens.
- Wider than about 10 mm: long stitches crush the foam into a flat top and snag easily.
- Wide shapes: split them into several columns side by side, or keep them flat.
Plan widths at the final size. A design that looks bold on screen can have 2 mm strokes at cap size.
Density and stitch length
Puff satin is sewn noticeably denser than flat satin, so the thread fully covers the foam and the closely spaced needle holes cut it cleanly along the edges. Use a tighter spacing than your flat satin (as a starting point, about 0.30 mm between same-direction stitches where flat satin uses 0.40 mm, a third more stitches) and adjust after a test sew. Too open and foam shows between stitches; too dense and the column flattens the foam it's meant to show off.
Underlay: almost none
Normal underlay would flatten the foam before the top stitches sew. Puff columns usually get no underlay, or at most a light run beneath the foam (sewn before the stop) to hold the fabric. Give puff columns a little more pull compensation than flat satin: the dense satin pulls hard, and the foam rounds the edges off, so columns sew narrower than drawn.
Capping the ends
An open column end — the bottom of an I, the ends of a C — leaves a flap of foam the satin doesn't cut. The fix is a cap: a few short stitches sewn along the column end, there and back, so the needle perforates the foam along the end line as well as the sides. The foam then tears away cleanly and the end is covered. Ends where two strokes join don't need caps, because the joining column covers them.
Sequencing and the machine stop
- Sew all flat parts first, including flat lettering, outlines and fills.
- Insert a stop (or a colour change to the same needle, depending on the machine) right before the first puff object.
- Sew puff objects centre-out on caps, like any cap design.
- Keep travel between puff columns short. Long jumps over the foam can tear it before it's stitched.
Testing
Sew a puff test on the same cap. Check that no foam peeks out at ends or along curves, that columns are evenly raised rather than flat in the middle, and that the foam tears away cleanly. A heat gun on low can shrink tiny remaining foam fibres.
In EasyDigitizer
Turn on 3D puff for any satin or lettering object. EasyDigitizer then switches the object to puff settings (0.30 mm satin, no underlay, extra pull compensation, columns at least 4 mm wide), warns you when the artwork's strokes are narrower or wider than puff can hold, and adds caps to every open column end automatically. Put the puff objects after the flat ones in the Sequence panel, with a stop before them.
Frequently asked questions
How thick should puff foam be?
2–3 mm is the most common for caps. Thicker foam needs wider columns and denser satin to cover it.
What is the minimum width for 3D puff?
About 3 mm. Narrower columns can't hold the foam up and it pokes through.
Do you use underlay with 3D puff?
Little or none under the puff satin, because underlay flattens the foam. A light run sewn before the foam goes down is fine.
Why is foam showing at the ends of my puff letters?
The open column ends aren't capped. Add short capping stitches along each open end so the needle cuts the foam there.